fgets.c

/* fgets( char *, int, FILE * )

   This file is part of the Public Domain C Library (PDCLib).
   Permission is granted to use, modify, and / or redistribute at will.
*/

#include <stdio.h>

#ifndef REGTEST
#include "_PDCLIB_io.h"

char * _PDCLIB_fgets_unlocked( char * _PDCLIB_restrict s, int size, FILE * _PDCLIB_restrict stream )
{
    if ( size == 0 )
    {
        return NULL;
    }
    if ( size == 1 )
    {
        *s = '\0';
        return s;
    }
    if ( _PDCLIB_prepread( stream ) == EOF )
    {
        return NULL;
    }
    char * dest = s;

    dest += _PDCLIB_getchars( dest, size - 1, '\n', stream );

    *dest = '\0';
    return ( dest == s ) ? NULL : s;
}

char * fgets( char * _PDCLIB_restrict s, int size, 
              FILE * _PDCLIB_restrict stream )
{
    _PDCLIB_flockfile( stream );
    char* r = _PDCLIB_fgets_unlocked( s, size, stream );
    _PDCLIB_funlockfile( stream );
    return r;
}

#endif

#ifdef TEST
#include "_PDCLIB_test.h"
#include <string.h>

int main( void )
{
    FILE * fh;
    char buffer[10];
    char const * fgets_test = "foo\nbar\0baz\nweenie";
    TESTCASE( ( fh = fopen( testfile, "wb+" ) ) != NULL );
    TESTCASE( fwrite( fgets_test, 1, 18, fh ) == 18 );
    rewind( fh );
    TESTCASE( fgets( buffer, 10, fh ) == buffer );
    TESTCASE( strcmp( buffer, "foo\n" ) == 0 );
    TESTCASE( fgets( buffer, 10, fh ) == buffer );
    TESTCASE( memcmp( buffer, "bar\0baz\n", 8 ) == 0 );
    TESTCASE( fgets( buffer, 10, fh ) == buffer );
    TESTCASE( strcmp( buffer, "weenie" ) == 0 );
    TESTCASE( feof( fh ) );
    TESTCASE( fseek( fh, -1, SEEK_END ) == 0 );
    TESTCASE( fgets( buffer, 1, fh ) == buffer );
    TESTCASE( strcmp( buffer, "" ) == 0 );
    TESTCASE( fgets( buffer, 0, fh ) == NULL );
    TESTCASE( ! feof( fh ) );
    TESTCASE( fgets( buffer, 1, fh ) == buffer );
    TESTCASE( strcmp( buffer, "" ) == 0 );
    TESTCASE( ! feof( fh ) );
    TESTCASE( fgets( buffer, 2, fh ) == buffer );
    TESTCASE( strcmp( buffer, "e" ) == 0 );
    TESTCASE( fseek( fh, 0, SEEK_END ) == 0 );
    TESTCASE( fgets( buffer, 2, fh ) == NULL );
    TESTCASE( feof( fh ) );
    TESTCASE( fclose( fh ) == 0 );
    TESTCASE( remove( testfile ) == 0 );
    return TEST_RESULTS;
}

#endif